TWI607879B - Optical laminate, polarizing plate and image display device using same - Google Patents

Description

Optical laminate, polarizing plate and image display device using same

The present invention relates to an optical laminate, a polarizing plate using the same, and an image display device.

In an image display device, an LCD (Liquid Crystal Display), an LCD equipped with a touch panel, an ELD (Electroluminescence Display), and an electronic paper have characteristics such as power saving, light weight, and thinness. It has been rapidly popularized in recent years in place of the previous CRT (Cathode-Ray Tube) display.

An optical layering system used for the surface or the inside of such an image display device is generally required to impart hardness so as not to be injured during use. Therefore, hardness is usually imparted by providing a hard coat layer or the like on a light-transmitting substrate. For example, in the LCD, a polarizing element is usually disposed on the image display surface side of the liquid crystal cell, and a hard coat film provided with a hard coat layer on the light-transmitting substrate is used as a polarizing plate protective film, thereby imparting hardness to the image display surface. .

Conventionally, as the light-transmitting substrate of the hard coat film, a film composed of a cellulose ester represented by triacetyl cellulose has been used. This is based on the advantages that the cellulose ester is excellent in transparency and optical uniformity, and there is almost no phase difference in the surface (the retardation value is low), so that the vibration direction of the incident linear polarization is rarely changed, and the liquid crystal display is displayed. Since the influence of the display quality of the device is small and the water permeability is moderate, it is advantageous in that the moisture remaining in the polarizing plate is transmitted through the optical laminate and dried when the polarizing plate made of the optical laminate is used.

However, the cellulose ester film is an unfavorable raw material in consideration of cost, and is resistant to moisture and heat. If a hard coating film made of a cellulose ester film is used as a polarizing plate protective film, it is in a high-temperature and humid environment. When used below, there is a disadvantage that the polarizing function or the color equal polarizing plate function is lowered.

Due to the problem of the above cellulose ester film, it has been proposed to use a transparent plastic substrate containing an acrylic resin as a main component, which is excellent in transparency, heat resistance, and mechanical strength, and is inexpensive compared with a cellulose ester film. Easy to get on the market.

However, in the optical layered body in which the hard coat layer is formed on one surface or both surfaces of the substrate containing the acrylic resin as a main component, there is a problem that the adhesion between the acrylic base material and the hard coat layer is inferior. Further, a refractive index difference occurs between the acrylic base material and the hard coat layer, and when a polarizing plate or the like is formed using the optical laminate, there is a problem that interference fringes are generated and the appearance is poor.

In view of the above problems, for example, Patent Document 1 discloses that, in addition to physical treatment such as corona discharge treatment or oxidation treatment on a substrate film, coating of a coating called an anchor agent or a primer is also performed. Thereafter, a hard coat layer is formed, whereby the adhesion between the base film and the hard coat layer is improved. Further, for example, Patent Document 2 discloses a method of forming irregularities at the interface between the base film and the hard coat layer.

However, in such methods, it is necessary to increase the steps necessary for the production of the hard coat film, and it is necessary to carry out special treatment, so that productivity is poor.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-81359

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-197670

Further, the acrylic substrate generally has a force for swelling the substrate as compared with the conventionally used cellulose ester film or polyester film, and the substrate is easily subjected to swelling due to the solvent. There is a problem that the substrate itself is broken during processing, and there is also a problem that the technique known from the prior transparent plastic substrate cannot be directly used for the acrylic substrate.

An object of the present invention is to provide an optical layered body having a resin layer on an acrylic substrate under the above-described conditions, which can be obtained in a relatively small number of manufacturing steps, and can be manufactured without being broken, and can be suppressed. The interference fringes are generated, and the adhesion between the acrylic base material and the resin layer is excellent.

In order to solve the above problems, the present inventors have conducted intensive studies on the above-mentioned problems, and found that in the optical layered body having a resin layer on one surface of the acrylic substrate, irregularities of a specific shape are provided at the interface between the acrylic substrate and the resin layer. This can solve the above problems. The present invention has been completed based on this finding.

That is, the present invention provides the following invention.

[1] An optical layered product having a resin layer on one surface of an acrylic substrate, and having a cross section in the thickness direction of the optical layered body, the acrylic substrate-resin layer interface has a mountain portion and a valley portion. The ridge line has a length of 31 to 45 μm in the reference length of 30 μm in the direction perpendicular to the thickness direction of the optical layered body.

[2] The optical layered product according to [1], wherein the cross section in the thickness direction of the optical layered body and the reference length of 30 μm in the direction perpendicular to the thickness direction of the optical layered body, the valley portion of the acrylic substrate-resin layer interface From the bottom of the deepest valley, the average depth of the top three in the order of depth is used as the reference depth, and then the top of the acrylic substrate-resin layer is topped from the highest peak. The average height of the top three in the sequence is used as the reference height, and the difference between the reference height and the reference depth is 0.3 to 3.5 μm.

[3] The optical layered body according to [1] or [2], wherein the ridge line has an average inclination angle θa of 15 to 48°.

[4] The optical layered body according to any one of [1] to [3] wherein the ridge line exhibits an average interval Sm of the unevenness of 0.5 to 7 μm.

[5] A polarizing plate comprising an optical layered body of any one of the at least one area layers [1] to [4] of the polarizing film.

[6] An image display device comprising the optical layered body of any one of [1] to [4] and/or the polarizing plate of [5].

The optical layering system of the present invention has a resin layer on an acrylic substrate, and can be obtained in a relatively small number of production steps, and the occurrence of interference fringes is suppressed, and the adhesion between the acrylic substrate and the resin layer is excellent.

1‧‧‧Acrylic substrate

2‧‧‧ resin layer

3‧‧‧hard coating

4‧‧‧Acrylic substrate-resin layer interface

4a‧‧‧Maximum point

4a-1‧‧‧y maximum maximum point (3 points)

4b‧‧‧minimum point

4b-1‧‧‧y coordinate minimum value (3 points)

5a‧‧‧Datum depth

5b‧‧‧Base height

h‧‧‧The difference between the reference height and the reference depth

h ₁ ~h ₁₂ ‧‧‧The difference between the extreme points of the adjacent

Fig. 1 is a scanning type transmission electron micrograph (STEM) showing a cross section of one aspect of the optical layered body of the present invention.

Fig. 2 is a scanning transmission electron micrograph (STEM) showing an acrylic substrate-resin layer interface in a cross section of one aspect of the optical layered body of the present invention.

Fig. 3 is a schematic view showing a cross section of one aspect of the optical layered body of the present invention.

Fig. 4 is a schematic view showing the ridgeline of the acrylic substrate-resin layer interface of the optical layered body of the present invention and the difference in height between the reference height and the reference depth.

Figure 5 is a view showing the ridge line of the acrylic substrate-resin layer interface of the optical layered body of the present invention, And a schematic diagram of the difference between the extreme points of the adjacent ones.

Fig. 6 is a scanning type transmission electron micrograph (STEM) showing a cross section of the optical layered body of the present invention obtained in Example 10.

Fig. 7 is a scanning type transmission electron micrograph showing the cross section of the optical layer-resin layer interface to the acrylic substrate-resin layer in the cross section of the optical layered body of the present invention obtained in Example 10 ( STEM).

Fig. 8 is a scanning type transmission electron micrograph (STEM) showing a cross section of the optical layered body obtained in Comparative Example 8.

Fig. 9 is a scanning type transmission electron micrograph showing an enlarged view of the interface from the hard coat layer-resin layer interface to the acrylic substrate-resin layer in the cross section of the optical layered body of the present invention obtained in Comparative Example 8. STEM).

The optical layering system of the present invention has a resin layer on one surface of the acrylic substrate, and is characterized in that it has a cross section in the thickness direction of the optical laminate, and the acrylic substrate-resin layer interface has a mountain portion and a valley. In the ridge line of the portion, the length of the ridge line in the reference length 30 μm in the direction perpendicular to the thickness direction of the optical layered body is 31 to 45 μm.

The optical layering system of the present invention has a resin layer on the acrylic substrate, and the interface between the acrylic substrate and the resin layer as shown in FIGS. 1 and 2 (hereinafter, simply referred to as an acrylic substrate-resin layer interface) ) has bumps.

Further, the length of the ridge line is preferably 31 to 45 μm, more preferably 32 to 42 μm. When the length of the ridge line is less than 31 μm, the unevenness of the interface between the acrylic base material and the resin layer is insufficient or the flat portion is increased, so that the adhesion between the acrylic base material and the resin layer interface is deteriorated. Or it is easy to produce interference fringes. On the other hand, if the length of the ridge line exceeds 45 μm, the haze of the optical layered body rises.

The length of the above ridge line is specifically measured in the manner shown below.

(Method for measuring the length of the ridgeline in the reference length of 30 μm)

Here, the length of the ridge line in the reference length of 30 μm can be measured, for example, by image analysis using the above-described cross section of the image analysis software (Image-Pro, manufactured by Media Cybernetic Co., Ltd.). Specifically, using the image analysis software by an electron microscope or the like, the image analysis software is used, and the reference length is taken on a straight line between the resin layer and the end portion of the base film in the image, and the image analysis software is used. The length of the above interface in the reference length. More specifically, using image analysis software Image-Pro Plus, Sharp Stack version 6.2, to form the measurement, calibration, space calibration wizard, active image, and operate in units (micron), combined with the scale of the image definition Line, for calibration. After calibration, the reference length is taken between two points at both ends of the interface by distance measurement. Then, using a manual measurement to create a trace line (threshold = 3, smoothing = 0, speed = 3, noise = 5, automatic), and finally compare the standard, thereby automatically measuring the curve, and reading the measured value As the length of the interface.

Further, in the optical layering system of the present invention, the cross section in the thickness direction of the optical layered body has a reference length of 30 μm in the direction perpendicular to the thickness direction of the optical layered body, and the valley portion of the acrylic substrate-resin layer interface is the deepest valley bottom. The average depth of the top three in the order of depth is used as the reference depth, and then the average height of the top three in the order of the highest peak from the top of the acrylic substrate-resin layer interface is used as the reference height. The difference between the reference height and the reference depth is preferably 0.3 to 3.5 μm, and the height difference is preferably 0.7 to 3.0 μm, and more preferably 1.0 to 2.5 μm. If the height difference is 3.5 μm or less, it is difficult to produce haze, and if it is 0.3 μm On the other hand, it is difficult to generate interference fringes, and the adhesion between the acrylic substrate-resin layer interface is improved.

The difference between the above reference depth and the average height is specifically measured as described below.

(Method for measuring the difference between the reference height and the reference depth)

As shown in Fig. 4, in the cross section in the thickness direction of the optical layered body, the acrylic substrate-resin layer interface has ridge lines having a mountain portion and a valley portion, and the y-axis is in the thickness direction of the optical layered body (where The resin layer side is a positive direction), and a reference length L of 30 μm is taken in the x-axis direction in the xy plane perpendicular to the y-axis direction, and the minimum length point 4b of the ridge line is obtained at the reference length L. Among them, 3 points (4b-1) are selected from the smallest of the y coordinates and the average y coordinate is used as the reference depth 5b. On the other hand, in the reference length L, the maximum point 4a of the ridge line is from the y coordinate Among the largest ones, 3 points (4a-1) are selected and the average y coordinate is used as the reference height 5a, and the difference (absolute value) between the reference depth 5b and the reference height 5a is the difference between the reference depth 5b and the reference height 5a.

The average inclination angle θa of the ridgeline of the optical layering system of the present invention is preferably from 15 to 48, more preferably from 20 to 48, still more preferably from 25 to 45. When the average inclination angle θa is 48° or less, the haze is less likely to occur, and when it is 15° or more, interference fringes are less likely to occur, and the adhesion between the acrylic base material and the resin layer interface is improved.

The above average tilt angle θa is specifically measured as described below.

(Method for measuring the average tilt angle θa)

As shown in Fig. 5, in the cross section in the thickness direction of the optical layered body, the acrylic substrate-resin layer interface has ridge lines having a mountain portion and a valley portion, and the thickness direction of the optical layered body is the y-axis (where The resin layer side is a positive direction), an xy plane which is an x-axis in a direction perpendicular to the y-axis, a reference length L of 30 μm is taken in the x-axis direction, and an extreme point of the ridge line is determined at the reference length L (maximum point 4a and minimum point 4b), the sum of the height difference (h ₁ ~ h ₁₂ , absolute value) of all the adjacent extreme points is recorded as the total height difference ΣH, at this time tan ^-1 (total The height difference ΣH/reference length L) is expressed as an average inclination angle θa.

Further, the average interval Sm of the concavities and convexities indicated by the ridge lines of the optical layering system of the present invention is preferably from 0.5 to 7 μm, more preferably from 1 to 6 μm, still more preferably from 2 to 5 μm. When the average interval Sm is 0.5 μm or more, haze is less likely to occur, and when it is 7 μm or less, interference fringes are less likely to occur, and the adhesion between the acrylic substrate-resin layer interface is improved.

Further, the above average interval Sm can be measured in accordance with JIS B0601 (1994).

Since the base material of the optical layering system of the present invention contains an acrylic resin, it is excellent in moisture heat resistance and smoothness, and wrinkles can be preferably prevented, compared with a substrate made of triacetyl cellulose (TAC). Produced. In the present specification, the term "acrylic resin" means an acrylic resin and/or a methacrylic resin.

<Acrylic substrate>

The acrylic resin to be contained in the acrylic base material is not particularly limited, and for example, one or two or more kinds of alkyl (meth)acrylates are preferably combined and polymerized. More specifically, It is preferably obtained by using methyl (meth) acrylate.

As the acrylic resin contained in the acrylic base material, a ring structure having an internal structure such as an acrylic resin having a lactone ring structure or an acrylic resin having a quinone ring structure can be used.

As a specific example of the above acrylic resin having a lactone ring structure, for example, It is described in Japanese Laid-Open Patent Publication No. 2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, JP-A-2005-146084, and the like.

The acrylic resin having a lactone ring structure preferably has a lactone ring structure represented by the following formula (1).

In the formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic group having 1 to 20 carbon atoms. Further, the above organic group may contain an oxygen atom.

In the structure of the acrylic resin having a lactone ring structure, the content of the lactone ring structure represented by the formula (1) is preferably from 5 to 90% by mass, more preferably from 10 to 70% by mass, further preferably. It is 10 to 60% by mass, preferably 10 to 50% by mass. When the content of the lactone ring structure represented by the above formula (1) is 5% by mass or more, the heat resistance, the solvent resistance, and the surface hardness are improved, and when the content is 90% by mass or less, the moldability is improved.

The weight average molecular weight of the acrylic resin having a lactone ring structure is preferably from 1,000 to 2,000,000, more preferably from 5,000 to 1,000,000, still more preferably from 10,000 to 500,000, most preferably from 50,000 to 500,000. When the weight average molecular weight of the acrylic resin having a lactone ring structure is within the above range, it is preferred from the viewpoint of the effects of the present invention described above.

Further, as the acrylic resin having the above quinone ring structure, for example, it can be listed An acrylic resin having a glutarylene imine structure or an N-substituted maleimide structure can be used.

The acrylic resin having a pentacomilin structure preferably has a glutarimide structure represented by the following formula (2).

In the above formula (2), R ⁴ and R ⁵ each independently represent a hydrogen atom or a methyl group, and R ⁶ represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group or a phenyl group.

Further, the glutarylenediamine structure can be formed, for example, by imidization of a (meth) acrylate polymer oxime by a sulfhydrylating agent such as methylamine. Here, "(meth)acrylic" means "acrylic acid" and "methacrylic acid".

The acrylic resin having the N-substituted maleimide structure has an N-substituted maleimide structure represented by the following formula (3).

In the above formula (3), R ⁷ and R ⁸ each independently represent a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group or a phenyl group.

Further, an acrylic resin having the above-described N-substituted maleimide structure in the main chain can be formed, for example, by copolymerizing N-substituted maleimide and (meth) acrylate.

Further, the acrylic resin-based glass transition point (Tg) is preferably from 100 to 140 ° C, more preferably from 105 to 135 ° C, still more preferably from 110 to 130 ° C. When the glass transition point (Tg) of the acrylic resin is 110° C. or more, the resin layer is less likely to be damaged by the solvent contained in the resin layer-forming composition, and when it is 150° C. or less, The interface of the resin layer is likely to form irregularities.

The acrylic base material may contain a resin other than the acrylic resin, but the ratio of the acrylic resin in the acrylic base material is preferably 80% by mass or more, and more preferably 90% by mass or more.

The thickness of the acrylic substrate is preferably 20 to 300 μm, more preferably 200 μm, and the lower limit is 30 μm. When the thickness of the acrylic substrate is 20 μm or more, the optical layered product of the present invention is less likely to wrinkle. On the other hand, when the thickness is 300 μm or less, the optical layered body of the present invention is thinned, and optical properties such as light transmittance are obtained. Excellent.

The acrylic substrate is preferably an extended acrylic substrate. By forming the stretched acrylic substrate, the strength or dimensional stability of the substrate can be improved.

The acrylic base material can be produced, for example, by subjecting particles (fragments) composed of a humidity-controlled acrylic resin to a usual melt extrusion, and then cooling the first surface to extend in the longitudinal direction, and then extending in the lateral direction. .

In the melt extrusion step, a screw having one axis, two axes, or two axes or more can be used, and the rotation direction, the number of revolutions, and the melting temperature of the screw can be arbitrarily set.

The above extension is preferably carried out in such a manner as to extend to a desired thickness. Extension ratio It is not limited, and is preferably 1.2 times or more and 4.5 times or less. The temperature and humidity at the time of extension can be arbitrarily determined. The extension method is a usual method.

The acrylic base material may contain acrylic rubber particles, an antioxidant, an ultraviolet absorber, a plasticizer, or the like.

Further, in the present invention, the acrylic substrate may be subjected to saponification treatment, glow discharge treatment, corona discharge treatment, plasma treatment, ultraviolet (UV) treatment, and flame treatment without departing from the gist of the present invention. Wait for surface treatment.

<Resin layer>

The resin layer is not particularly limited, and for example, it is preferably a hardening of a free-radiation curable resin composition A containing a monofunctional to trifunctional (meth) acrylate, particularly preferably a difunctional (meth) acrylate. Things. In the case of using a monofunctional or trifunctional (meth) acrylate, it is preferably used in combination with a difunctional (meth) acrylate.

Specific examples of the difunctional (meth) acrylate include dialkyl (meth) acrylate and polyalkylene glycol di (meth) acrylate. Or 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, or the like. In particular, in the difunctional (meth) acrylate, from the viewpoint of suppressing breakage of the substrate caused by the free radiation curable resin composition A and control of the surface unevenness, the polyalkylene glycol is particularly preferable. Di(meth)acrylate is the best.

Further, examples of the polyalkylene glycol di(meth)acrylate include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. Polyethylene glycol di(meth)acrylate such as acrylate, polypropylene glycol di(meth)acrylate such as dipropylene glycol di(meth)acrylate, and dibutylene glycol di(meth)acrylate, Tributyl diol di(meth) acrylate, tetrabutyl diol Polybutylene glycol di(meth)acrylate such as di(meth)acrylate.

In the present specification, the composition of the radiation curable resin is an electron beam curable resin composition and/or an ultraviolet curable resin composition.

In the present specification, the term "(meth)acrylate" means methacrylate and acrylate.

Specific examples of the monofunctional (meth) acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and hexyl (meth)acrylate. Cyclohexyl methacrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, alkylene glycol mono (meth) acrylate (ethylene glycol mono (meth) acrylate , propylene glycol mono (meth) acrylate, butane diol mono (meth) acrylate, etc.) or polyalkylene glycol mono (meth) acrylate (polyethylene glycol mono (meth) acrylate, polypropylene glycol Mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, etc.), preferably alkylene glycol mono (meth) acrylate.

Specific examples of the trifunctional (meth) acrylate include isomeric cyanuric acid triacrylate, polyalkylene glycol tri(meth) acrylate, and trimethylolpropane tri(meth)acrylic acid. Ester, pentaerythritol tri(meth)acrylate, and the like.

Further, PEO (polyethylene oxide) modified products and EO (ethylene oxide) modified products of the above-mentioned monofunctional, difunctional and trifunctional compounds are also preferred.

In the case where the above-mentioned free radiation curable resin composition A contains a difunctional (meth) acrylate and a monofunctional (meth) acrylate or a trifunctional (meth) acrylate, preferably a difunctional (meth) acrylate The mass ratio of the ester is greater than the total mass ratio of the monofunctional (meth) acrylate and the trifunctional (meth) acrylate.

The above-mentioned free-radiation curable resin composition A may further contain a monofunctional to trifunctional (methyl) group. The photopolymerizable monomer, the photopolymerizable oligomer, and the photopolymerizable polymer other than the acrylate include an initiator in the case of an ultraviolet curable resin composition.

(difunctional (meth) acrylate)

The difunctional (meth) acrylate is preferably one having a molecular weight of from 180 to 1,000, more preferably from 200 to 750, and particularly preferably having a molecular weight of from 220 to 450. When the molecular weight of the difunctional (meth) acrylate is within the above range, the length of the ridge line in the reference length of 30 μm, the difference in height between the reference height and the reference depth, and the average inclination angle θa can be easily obtained, and the adhesion or Excellent interference fringe prevention.

The amount of the difunctional (meth) acrylate in the composition of the free radiation curable resin composition A is more preferably from 50 to 100% by mass, particularly preferably from 70 to 100% by mass, based on the mass of the solid content. In the case of using a difunctional (meth) acrylate in combination with a monofunctional (meth) acrylate and/or a trifunctional (meth) acrylate, a monofunctional (meth) acrylate in the free radiation curable resin composition A The blending amount of the trifunctional (meth) acrylate is preferably set to the remainder of the above-mentioned difunctional (meth) acrylate blending amount.

Further, when a functional component such as a refractive index adjusting material or an antistatic material is added to the resin layer, it is presumed that as shown in FIG. 7, the functional component is not present in the lower portion of the resin layer but is densely concentrated on the upper portion. Therefore, the solvent to be described later is volatilized, and the material component of the dissolved acrylic substrate flows out into the resin layer to form irregularities at the interface of the acrylic substrate-resin layer. Further, by forming an appropriate unevenness at the interface, the adhesion is good and the interference fringe prevention property is also good, and the target function (antistatic property, high refractive index, low refractive index, etc.) can be favorably produced. ), so it is also better.

(photopolymerizable polymer)

The photopolymerizable polymer preferably has a (meth)acryl fluorenyl group as a functional group, and preferably has a functional group number of 10 to 250, more preferably 10 to 100 functional groups, and further Jia is a functional group of 10 to 50.

The weight average molecular weight of the photopolymerizable polymer is preferably from 10,000 to 100,000, more preferably from 12,000 to 40,000.

The amount of the photopolymerizable polymer in the composition of the radiation curable resin composition A is preferably from 0 to 40% by mass, more preferably from 0 to 30% by mass, based on the mass of the solid content.

(photopolymerizable oligomer)

As the photopolymerizable oligomer, a bifunctional or higher functional group may be used, and a (meth)acryl fluorenyl group is preferably used as the functional group, and the number of functional groups is preferably 2 to 30, and more preferably the number of functional groups is 2 to 20, and more preferably 3 to 15 functional groups.

The weight average molecular weight of the photopolymerizable oligomer is preferably from 1,000 to 10,000, more preferably from 1,500 to 10,000.

The amount of the photopolymerizable oligomer in the composition of the radiation curable resin composition A is preferably from 0 to 40% by mass, more preferably from 0 to 30% by mass, based on the mass of the solid content.

(Photopolymerizable monomer other than monofunctional to trifunctional (meth) acrylate)

Examples of the photopolymerizable monomer include one or two or more unsaturated bonds such as a compound having a (meth) acrylonitrile group. Examples of the monofunctional monomer having one unsaturated bond include styrene, methylstyrene, and N-vinylpyrrolidone. Examples of the polyfunctional monomer having two or more unsaturated bonds include pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol five ( A methyl group acrylate or the like, and a polyfunctional compound modified by ethylene oxide (EO) or the like.

By using a monofunctional monomer, the refractive index adjustment becomes easy, and a resin layer having a higher refractive index can be formed. On the other hand, when a polyfunctional monomer is used, the hardness is good.

The molecular weight of the photopolymerizable monomer is preferably from 200 to 1,000, more preferably from 250 to 750.

The amount of the photopolymerizable monomer other than the monofunctional to trifunctional (meth) acrylate in the composition of the free radiation curable resin composition A is preferably from 0 to 40% by mass, more preferably from 0 to 30, based on the amount of the solid content component. quality%.

The free radiation curable resin composition A preferably further contains a solvent.

Preferably, the solvent is selected such that the acrylic substrate is moderately swollen. Among them, the acrylic substrate is different from the conventional TAC substrate, and can be swollen with almost all kinds of solvents. Therefore, the influence of the solvent is strong, and the swelling degree is too strong and the film is broken. Therefore, the following solvent is selected, whereby the substrate can be appropriately swollen, and the resin component of the substrate and the resin constituting the resin layer can be formed. The balance of component movement becomes moderate, and a better ridgeline can be obtained at the interface.

Further, the solvent can be selected and used depending on the type and solubility of the resin component to be used. The solvent is preferably an alcohol (methanol, ethanol, isopropanol or 1-butanol), and the other solvent types tend to have a higher carbon number, and those having a faster evaporation rate are preferred. tendency. For example, the ketones are exemplified by methyl isobutyl ketone, the aromatic hydrocarbons are exemplified by toluene, the diols are propylene glycol monomethyl ether, and the like, and these may be mixed solvents.

In the present invention, in particular, the compatibility with the resin and the coating property are excellent, and the special uneven shape of the present invention is formed at the interface between the acrylic substrate and the resin layer, and the substrate is not broken during processing. For the reason, it is particularly preferable to contain one or more selected from the group consisting of methyl isobutyl ketone, isopropyl alcohol, 1-butanol, and propylene glycol monomethyl ether. When it is such a solvent, an acrylic base material can swell moderately without breaking.

Conversely, esters (methyl acetate, ethyl acetate, propyl acetate, butyl acetate, etc.) or ketones (acetone, methyl ethyl ketone, cyclohexanone, diacetone alcohol), 赛路苏, ether Class (two Alkane, tetrahydrofuran, propylene glycol monomethyl ether acetate, etc.), aliphatic hydrocarbons (hexane, etc.), aromatic hydrocarbons (xylene), halogenated hydrocarbons (dichloromethane, dichloroethane, etc.), race Lu Su (Methyl Cyrus, Ethyl Lucas, etc.), Cypress Acetate, Azadiracht (Dimethyl Azine, etc.), Amidoxime (Dimethylformamide, Dimethyl) Since the acrylamide base material is excessively swelled by the acetonitrile, it is preferable not to use when tension is applied to the base material.

In the above-mentioned free radiation curable resin composition A, the content ratio of the solvent is not particularly limited. For example, the preferred solvent is preferably 30 parts by mass based on 100 parts by mass of the solid content of the free radiation curable resin composition A. ~300 parts by mass, more preferably 100 to 220 parts by mass. When the content ratio of the solvent is within the above range, the length of the ridge line in the reference length of 30 μm, the height difference between the reference height and the reference depth, and the average inclination angle θa can be easily obtained. When the content ratio of the solvent is 100 parts by mass or more based on 100 parts by mass of the solid content component of the free radiation curable resin composition A, the length of the ridge line in the reference length of 30 μm, the height difference between the reference height and the reference depth, and the average value When the inclination ratio θa is increased, and the solvent content ratio is 300 parts by mass or less based on 100 parts by mass of the solid content component of the free radiation curable resin composition A, the length, the reference height, and the reference of the ridge line in the reference length of 30 μm. The depth difference and the average tilt angle θa are reduced.

The acrylic substrate-resin layer interface in the optical layered body of the present invention has a ridge line of a mountain portion and a valley portion, which is obtained by containing a difunctional (meth) group such as a polyalkylene glycol di(meth)acrylate. The acrylate free radiation curable resin composition A is effectively obtained in combination with the above preferred solvent. For example, the acrylic substrate is moderately swollen by a solvent, and accordingly, it has an appropriate molecular weight. A difunctional (meth) acrylate or the like penetrates into the acrylic substrate. Further, when the component of the resin layer penetrates into the acrylic substrate, the material component of the acrylic substrate is extruded in the direction of the resin layer, and the solvent is volatilized from the acrylic substrate toward the air surface of the resin layer. The material component of the swollen acrylic substrate also penetrates into the resin layer. It is considered that each component moves from the upper portion to the lower portion and from the lower portion to the upper portion as described above, whereby ridge lines having appropriate mountain portions and valley portions are formed at the interface, and the adhesion is good and the interference fringe prevention property is also good. The configuration or average tilt angle of the ridge lines can be adjusted by controlling the composition of the resin layer or the kind of the solvent and the drying temperature.

In order to form the above-described specific ridgeline structure at the interface of the acrylic substrate-resin layer of the optical layered body of the present invention, as one example of a preferable production method, there is the following method: (first step) will be a polyalkylene glycol di A difunctional di(meth)acrylate such as methyl acrylate is used as a main component, and a free radiation curable resin composition A containing a solvent is applied to an acrylic substrate, and (second step) is cured by free radiation. The solvent, the monomer, and the like in the resin composition A swell the acrylic substrate, and (in the third step), while drying the solvent at an appropriate drying temperature, the acrylic substrate is swollen while the material component of the acrylic substrate is used. It is preferable to move the component of the radical radiation curable resin composition A to form an uneven ridge line at the interface of the acrylic base material/resin layer, and (the fourth step) irradiate the free radiation to harden the free radiation curable resin composition A. However, the method of forming the resin layer is not a method for producing the above specific ridge line, and the method of manufacturing the optical layered body is not Limited to this.

When a functional component such as a refractive index adjusting material or an antistatic material is added to the resin layer, the functional component may be distributed over the upper portion of the resin layer by the reverse flow of the material component of the acrylic substrate. Since the functional component is densely concentrated on the surface side of the optical layered body, the function of the target (antistatic property, high refractive index, low refractive index, etc.) can be favorably produced, which is preferable.

The free-radiation curable resin composition A may further contain a solvent-drying resin. By using a solvent-drying type resin in combination, it is possible to effectively prevent film defects on the coated surface. In addition, the above-mentioned solvent-drying type resin refers to a resin which forms a film only by drying a solvent added by adjusting a solid content component when a thermoplastic resin or the like is applied.

The solvent-drying type resin is not particularly limited, and a thermoplastic resin can be usually used.

The thermoplastic resin is not particularly limited, and examples thereof include a styrene resin, a (meth)acrylic resin, a vinyl acetate resin, a vinyl ether resin, a halogen-containing resin, and an alicyclic olefin resin. A polycarbonate resin, a polyester resin, a polyamide resin, a cellulose derivative, a polyoxyn resin, a rubber or an elastomer. The above thermoplastic resin is preferably amorphous and soluble in an organic solvent (particularly a common solvent which can dissolve a plurality of polymers or curable compounds). In particular, a styrene resin, a (meth)acrylic resin, an alicyclic olefin resin, a polyester resin, or a cellulose derivative is preferred from the viewpoint of film formability, transparency, and weather resistance. (cellulose esters, etc.) and the like.

The above-mentioned initiator is not particularly limited, and a known one can be used, for example, as a photopolymerization initiator. Specific examples thereof include acetophenones, diphenylketones, and Michler benzophenone benzoate. (Michler-benzoyl benzoate), α-amyloxim ester, thioxanthone, propiophenone, benzil, benzoyl, sulfhydryl oxidation Acylphosphine oxides. Further, it is preferably used by mixing a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, and poly-n-butylphosphine.

In the case where the photopolymerizable monomer/oligomer/polymer is a resin having a radical polymerizable unsaturated group, the photopolymerization initiator is preferably a acetophenone or a diphenyl ketone. Separately or in combination, such as thioxanthone, benzoin, and benzoin methyl ether, 1-hydroxycyclohexyl phenyl ketone is preferred because it is compatible with free radiation-curable resin and has less yellowing. . Further, in the case where the photopolymerizable monomer/oligomer/polymer has a cationically polymerizable functional group, the photo-polymerization initiator is preferably an aromatic diazonium salt, an aromatic sulfonium salt or a fragrance. The cerium salt, the metallocene compound, the benzoin sulfonate or the like is used singly or as a mixture.

In the ultraviolet curable resin composition, the content of the above-mentioned initiator is preferably 1 to 10 by mass based on 100 parts by mass of the total of the photopolymerizable monomer, the photopolymerizable oligomer, and the photopolymerizable polymer. Share. When the content of the initiator is 1 part by mass or more, it is preferably from the viewpoint of the hardness of the resin layer of the optical layered product, and when it is 10 parts by mass or less, deterioration of the resin due to excessive residue of the initiator can be suppressed. Further, it is possible to prevent an increase in cost and obtain a pencil hardness of the target resin layer or the surface of the hard coat layer described later.

The lower limit of the content of the above-mentioned initiator is 2 parts by mass, and more preferably 8 parts by mass, based on 100 parts by mass of the total of the photopolymerizable monomer, the photopolymerizable oligomer, and the photopolymerizable polymer. . The above hardening is more sure by the content of the above-mentioned initiator.

By including the functional component in the above-mentioned free radiation curable resin composition A, the resin layer can be further functionalized.

Examples of the functional component include an antistatic agent, a refractive index adjuster, an antifouling agent, and a slippery A user of a usual optical sheet such as a agent, an anti-glare agent, or a hard coat imparting agent.

The above-mentioned free radiation curable resin composition A may also contain an antistatic agent.

The antistatic agent is preferably an organic one, and more specifically, an ion such as a lithium ion salt, a quaternary ammonium salt or an ionic liquid, or an electron such as polythiophene, polyaniline, polypyrrole or polyacetylene. Conductive.

Further, the free radiation curable resin composition A may contain an antifouling agent such as fluorine or polyfluorene.

In the case of using the above functional component, the content thereof is preferably from 1 to 30% by mass based on the total mass of the total solid content in the free radiation curable resin composition A.

Furthermore, the optical laminate of the present invention is formed by using a free radiation curable resin composition A containing an antistatic agent to form a resin layer (that is, a case where the resin layer contains an antistatic agent), by the above-mentioned difunctional (A) The combination of acrylates, and for the above reasons, the antistatic agent is biased on the upper surface of the resin layer, thereby further improving the antistatic property. In addition, when a resin layer is formed by using the free radiation curable resin composition A containing ultrafine particles such as ceria or alumina as a hard coatability imparting agent (that is, when the resin layer contains a hard coat imparting agent), By the combination with the above-mentioned polyalkylene glycol di(meth)acrylate, and for the above reasons, the hard coat property imparting agent is biased on the upper surface of the resin layer, thereby further improving the hard coat performance.

The method for producing the above-mentioned free radiation curable resin composition A is not particularly limited as long as the components can be uniformly mixed, and can be, for example, a known apparatus such as a paint shaker, a bead mill, a kneader or a stirrer.

In addition, the method of applying the above-mentioned free radiation curable resin composition A to the above acrylic substrate is not particularly limited, and examples thereof include a spin coating method and a dipping method. Spray method, die coating method, bar coating method, gravure coating method, roll coating method, meniscus coater method, soft printing method, screen printing method, droplet A known method such as a bead coater.

The coating film formed by applying the above-mentioned free radiation curable resin composition A to the acrylic substrate is preferably heated and/or dried as necessary, and is cured by irradiation with an active energy ray or the like.

In the drying step, the drying time is preferably from 20 seconds to 2 minutes, more preferably from 30 seconds to 1 minute. Further, in the drying step, the drying temperature is preferably from 40 to 90 ° C, more preferably from 50 to 80 ° C. When the drying temperature exceeds 100 ° C, even if a solvent having a preferred swelling property against acrylic acid is selected, there is a case where the penetration of the solvent is increased and the substrate is broken. Therefore, the drying temperature is preferably such that any solvent is used. It is below 90 °C. For example, a preferred solvent is methyl isobutyl ketone. Even in the case of this solvent, when the drying temperature is 100 ° C and the tension is applied, the acrylic substrate may be broken.

The minimum temperature is preferably as long as the solvent can be dried, and is preferably 50 ° C or higher. For example, in the case of methyl isobutyl ketone and the drying temperature is 30 ° C, if the drying is insufficient and the curing is performed directly by ultraviolet rays or the like, the hardening proceeds in this case, and an unhardened portion is also produced. At this time, there is a case where the adhesion is lowered.

Examples of the active energy ray irradiation include irradiation with ultraviolet rays or electron beams.

Specific examples of the ultraviolet light source to be irradiated with ultraviolet rays include light sources such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black fluorescent lamp, and a metal halide lamp. Further, as the wavelength of the ultraviolet light, a wavelength region of 190 to 380 nm can be used.

Specific examples of the electron beam source to be irradiated by the electron beam include a Cockcroft Walton type, a Van de Graaff type, a resonant transformer type, and an insulated core transformer type. Or various electron beam accelerators such as linear type, dynamitron type, and high frequency type.

Further, the film thickness of the resin layer (at the time of curing) is preferably 0.5 to 100 μm, more preferably 0.8 to 20 μm; it is easier to form an uneven ridge line at the interface of the acrylic substrate/resin layer, and curling The prevention property or the crack prevention property is particularly excellent, so it is preferably in the range of 3.5 to 13 μm.

Further, in order to improve the adhesion, the film thickness of the resin layer is preferably 0.8 μm or more and less than 3 μm. The film thickness of the resin layer is 0.8 μm, which is also the minimum film thickness required for forming the optimum ridge line of the uneven shape. When the film thickness of the resin layer is 0.8 μm or more and less than 3 μm, the difference between the reference height and the reference depth is preferably 0.3 to 1.5 μm.

In addition, the height difference is set to satisfy the relationship between the film thickness of the resin layer and the height difference regardless of the film thickness of the resin layer.

The film thickness of the resin layer was observed by an electron microscope (SEM, TEM, STEM), and the average value (μm) obtained by measuring any 10 points was measured.

Further, the optical layered body of the present invention may directly have one or more selected from the group consisting of a low refractive index layer, a hard coat layer, an antifouling layer, an antiglare layer, an antistatic layer, and a high refractive index layer on the resin layer. .

<hard coating>

The hard coat layer is preferably composed of a cured product of the free radiation curable resin composition B.

Hard coating is a pencil hardness test (load 4.9N) with hardness of JIS K5600-5-4 (1999) It is preferably H or more, more preferably 2H or more. Further, the hard coat layer may be a functional component.

The details of the free-radiation-curable resin composition B forming the hard coat layer are the same as those of the above-mentioned free-radiation curable resin composition A except that a difunctional (meth) acrylate is an essential component.

Further, in the composition of the radiation curable resin composition B, the amount of the photopolymerizable monomer (especially a polyfunctional monomer) is preferably from 30 to 100% by mass, more preferably from 40 to 90% by mass, still more preferably 50~80% by mass. In this case, the remaining portion of the free radiation curable resin composition B is preferably at least one of a photopolymerizable oligomer and a photopolymerizable polymer.

Further, the method of forming the hard coat layer is the same as that of the above resin layer. The details of the other hard coat layers are also the same as those of the above resin layer.

In the present invention, it is preferred to laminate a hard coat layer over the resin layer. In order to obtain the hardness as an optical laminate, it is conceivable to make the resin layer itself high in hardness. However, when a high hardness of 2H or more is formed directly on the acrylic substrate, that is, a material having a polyfunctional reactive functional group in the resin layer, a partial pressure is applied to the hard coat layer, and the like. The acrylic substrate is susceptible to cracking. Therefore, in the optical laminate of the present invention, since the resin layer is between the acrylic substrate and the hard coat layer, the impact of the hard coat layer is not directly transmitted to the acrylic substrate, and it has a buffering effect. Further, by forming the structure of the resin layer/hard coat layer, the hardness can be improved as compared with the case of merely laminating the hard coat layer.

However, in the case of a laminated hard coat layer or the like, a new interface is formed with the resin layer, that is, a portion where interference fringes are generated is increased. In this case, it is more important that the refractive index of the layer of the laminate is as close as possible to the layer below it. Therefore, in order to maintain the interference fringe prevention property well, the refractive index of the hard coat layer It is preferably substantially the same as the refractive index of the resin layer, and preferably has a refractive index difference of 0.03 or less.

The film thickness of the hard coat layer is preferably from 1 to 20 μm, more preferably from 3.5 to 13 μm.

<low refractive index layer>

The optical layered body of the present invention preferably has a low refractive index layer on the above hard coat layer.

The low refractive index layer is preferably formed by using a composition for forming a low refractive index layer containing 1) a resin containing low refractive index inorganic fine particles such as cerium oxide or magnesium fluoride, and 2) low refractive index. The resin is a fluorine-based resin of a resin, 3) a fluorine-based resin containing low-refractive-index inorganic fine particles such as cerium oxide or magnesium fluoride, and 4) a low refractive index inorganic thin film such as cerium oxide or magnesium fluoride. As the resin other than the fluorine-based resin, the same resin as the above-mentioned acrylic resin can be used.

Further, the above-mentioned cerium oxide is preferably hollow cerium oxide fine particles, and the hollow cerium oxide fine particles can be produced, for example, by the production method described in the examples of JP-A-2005-099778.

The refractive index of the low refractive index layer is preferably 1.47 or less, and particularly preferably 1.42 or less. Further, the thickness of the low refractive index layer is not limited, and it is usually set in the range of about 10 nm to 1 μm.

As the fluorine-based resin, a polymerizable compound containing at least a fluorine atom in a molecule or a polymer thereof can be used. The polymerizable compound is not particularly limited, and for example, a hardening reactive group such as a functional group which is cured by free radiation and a polar group which is thermally cured is preferably used. Further, it may be a compound having such reactive groups at the same time. The polymer is not a reactive group as described above with respect to the polymerizable compound.

As the polymerizable compound having the functional group which is hardened by the above-mentioned free radiation, a fluorine-containing monomer having an ethylenically unsaturated bond can be widely used. More specifically, fluoroolefins (for example, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-) can be exemplified. 1,3-two Oral (perfluoro-2,2-dimethyl-1,3-dioxol), etc.). As the (meth) propylene oxime group, there are: 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, (methyl) a (meth) acrylate compound having a fluorine atom in a molecule such as 2-(perfluorodecyl)ethyl acrylate, α-trifluoromethyl methacrylate or α-trifluoromethyl acrylate; Fluorinated polyfunctional (meth) acrylate compound having at least 3 fluorine atoms and having a fluoroalkyl group having 1 to 14 carbon atoms, a fluorocycloalkyl group or a fluoroalkylene group, and at least 2 (meth) propylene fluorenyloxy groups Wait.

The preferred one of the polar groups to be thermally cured is, for example, a hydrogen bond forming group such as a hydroxyl group, a carboxyl group, an amine group or an epoxy group. These are excellent not only in adhesion to a coating film, but also in affinity with inorganic ultrafine particles such as cerium oxide. Examples of the polymerizable compound having a thermosetting polar group include a 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer; a vinyl fluoride-hydrocarbon vinyl ether copolymer; an epoxy resin and a polyurethane. Fluorine-modified products of various resins such as cellulose, phenols, and polyimine.

The polymerizable compound having the above-mentioned functional group which is hardened by free radiation and the polar group which is thermally hardened may, for example, be a part of acrylic acid or methacrylic acid and a completely fluorinated alkyl group, an alkenyl group, an aryl ester group, Full or partial fluorinated vinyl ethers, fully or partially fluorinated vinyl esters, fully or partially fluorinated ketenes, and the like.

Further, examples of the fluorine-based resin include the following.

a polymer of a monomer or a monomer mixture containing at least one fluorine-containing (meth) acrylate compound having a polymerizable compound of the above-mentioned free radiation curable group; the above fluorine-containing (meth) acrylate At least one of the complexes, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethyl (meth)acrylate a copolymer of a (meth) acrylate compound having no fluorine atom in the molecule of hexyl ester; vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoropropene, 1, A homopolymer or copolymer of a fluorine-containing monomer such as 1,2-trichloro-3,3,3-trifluoropropene or hexafluoropropylene. A polyfluorene-containing vinylidene fluoride copolymer obtained by including a polyfluorene oxide component in the copolymer may also be used. As the polyoxymethylene component in this case, (poly)dimethyloxane, (poly)dimethoxydecane, (poly)diphenyloxirane, (poly)methylphenylhydrazine can be exemplified. Oxyalkane, alkyl modified (poly)dimethyloxane, azo-containing (poly)dimethyloxane, dimethylpolyfluorene, phenylmethylpolyoxyl, alkyl Poly-oxygen, aralkyl modified poly-oxygen, fluoropolyoxygen, polyether modified poly-oxygen, fatty acid ester modified polyoxyl, methyl hydrogen polyoxyl, sterol-containing polyfluorene Oxygen, alkoxy-containing polyfluorene oxide, phenol group-containing polyfluorene oxide, methacrylic acid modified polyfluorene oxide, acrylic acid modified polyfluorene oxide, amine modified polyoxymethylene, carboxylic acid modified polyoxyl Methanol modified polyfluorene oxide, epoxy modified polyfluorene oxide, sulfhydryl modified polyfluorene oxide, fluorine modified polyfluorene oxide, polyether modified polyfluorene and so on. Among them, those having a dimethyl fluorene structure are preferred.

Further, a non-polymer or a polymer composed of the following compounds can also be used as the fluorine-based resin. That is, a compound obtained by reacting a fluorine-containing compound having at least one isocyanate group in the molecule with a compound having at least one functional group reactive with an isocyanate group such as an amine group, a hydroxyl group or a carboxyl group in the molecule; A fluorine-containing polyhydric alcohol such as a fluorine-containing polyether polyol, a fluorine-containing polyhydric alcohol, a fluorine-containing polyester polyol, or a fluorine-containing ε-caprolactone-modified polyol, and a compound obtained by reacting a compound having an isocyanate group Compounds, etc.

Further, the low refractive index layer-forming composition may contain each of the thermoplastic resins described above in addition to the above-mentioned polymerizable compound or polymer having a fluorine atom. Further, When a curing agent for curing a reactive group or the like is used, various additives and solvents for improving coating properties or imparting antifouling properties are used.

In the formation of the low refractive index layer, it is preferable that the viscosity of the composition for forming the low refractive index layer is 0.5 to 5 mPa ‧ (25 ° C), preferably 0.7 to 3 mPa, for obtaining a preferable coating property. ‧ s (25 ° C) range. The antireflection layer excellent in visible light can be realized, and a film which is uniform and has no uneven coating can be formed, and a low refractive index layer which is particularly excellent in adhesion can be formed.

The hardening means of the resin may be the same as the hardening means of the aforementioned hard coat layer. In the case where a heating means is used for the hardening treatment, it is preferred to add a thermal polymerization initiator which starts polymerization of a polymerizable compound by heating, for example, by generating a radical in the composition for forming a low refractive index layer.

The optical layered body of the present invention preferably has a total light transmittance of 80% or more. If it is less than 80%, in the case of being mounted on an image display device, there is a possibility that the color reproducibility or visibility is impaired, and the desired contrast cannot be obtained. The above total light transmittance is more preferably 90% or more.

The total light transmittance can be measured by a method according to JIS K-7361 using a fog meter (manufactured by Murakami Color Research Laboratory, product number: HM-150).

Further, the optical layering system of the present invention preferably has a haze of 1% or less. When it is 1% or less, the desired optical characteristics can be obtained, and the visibility of the optical layered body of the present invention on the image display surface is not deteriorated. The haze is more preferably 0.8% or less, further preferably 0.5% or less.

The haze can be measured by a method according to JIS K-7136 using a fog meter (manufactured by Murakami Color Research Laboratory, product number: HM-150).

The polarizing plate of the present invention is formed by the optical layered body of the present invention in at least one area layer of the polarizing film.

The polarizing film is not particularly limited, and for example, it can be dyed with iodine or the like and stretched. A polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, or the like. In the lamination treatment of the polarizing film and the optical layered body, it is preferred to subject the acrylic substrate to a saponification treatment. By the saponification treatment, the adhesion is good and an antistatic effect is also obtained.

The present invention also provides an image display device including the optical layered body and/or the polarizing plate.

Examples of the image display device include a television, a computer, an LCD, a PDP (Plasma Display Panel), an FED (field emission display), an ELD (organic EL, inorganic EL), a CRT, and a flat panel. A PC (tablet PC), an electronic paper, a mobile phone, etc., can be preferably used for a touch panel used in an image display device or the like.

The above-mentioned representative example of the LCD includes a transmissive display body and a light source device that illuminates the transmissive display body from the back surface. In the case where the image display device of the present invention is an LCD, the optical layered body of the present invention and/or the polarizing plate of the present invention are formed on the surface of the transparent display body. In the case where the image display device with the touch panel is mounted, it is not limited to the surface, and can also be used as a transparent substrate constituting the touch panel.

The above-mentioned representative example is an LCD having a transmissive display and a light source device that illuminates the transmissive display from the back. In the case where the image display device of the present invention is an LCD, the optical layered body of the present invention and/or the polarizing plate of the present invention are formed on the surface of the transparent display body. Further, depending on the case of the image display device on which the touch panel is mounted or the case of the LCD or the like, it is not limited to the surface, and may be used as a transparent substrate or the like constituting the inside of the device.

In the liquid crystal display device of the present invention, the light source of the light source device is irradiated from the lower side of the optical laminate or the polarizing plate. Furthermore, it is also possible to insert between the liquid crystal display element and the polarizing plate. Into the phase difference plate. An adhesive layer may be provided between the respective layers of the liquid crystal display device as needed.

Here, in the case where the liquid crystal display device of the optical layered body of the present invention is provided, the liquid crystal display device is not particularly limited as a backlight source, and is preferably a white light emitting diode (white LED), and the image of the present invention. The display device is preferably a VA mode or IPS mode liquid crystal display device having a white light-emitting diode as a backlight source.

The above-mentioned white LED refers to a phosphor type, that is, an element which emits white by combining a light-emitting diode using a blue light or ultraviolet light of a compound semiconductor and a phosphor. Among them, a white light-emitting diode composed of a light-emitting element in which a blue light-emitting diode of a compound semiconductor and a yttrium aluminum garnet-based yellow phosphor are combined has a continuous and wide range of light-emitting spectra. Therefore, the improvement of the antireflection performance and the contrast of the bright portion is effective, and the luminous efficiency is also excellent. Therefore, it is preferable as the backlight source of the present invention. Moreover, since the white LED with low power consumption can be widely used, the effect of energy saving can also be achieved.

Further, in the above-mentioned VA (Vertical Alignment) mode, when liquid crystal molecules are aligned perpendicular to the substrate of the liquid crystal cell when no voltage is applied, the liquid crystal molecules are displayed in a dark display, and the liquid crystal molecules are displayed by the application of a voltage. The action mode for the light display.

Further, in the above-described IPS (In-Plane Switching) mode, the liquid crystal is rotated in the surface of the substrate by applying a transverse electric field to an interdigitated array electrode provided on one of the liquid crystal cells. The way it is displayed.

The PDP of the image display device includes a surface glass substrate on which an electrode is formed on the surface, and a discharge gas is disposed to face the surface glass substrate, and an electrode and a minute groove are formed on the surface, and a groove is formed in the groove. The back glass substrate of the red, green, and blue phosphor layers. In the case where the image display device of the present invention is a PDP, the surface glass substrate is The surface or the front panel (glass substrate or film substrate) thereof is provided with the above optical laminate.

The image display device may be an ELD device that displays a zinc sulfide, a diamine substance, a light-emitting body that emits light when a voltage is applied, and a light-emitting body, and controls the voltage applied to the substrate, or converts the electric signal. An image display device such as a CRT that produces an image visible to the human eye for light. In this case, the optical layered body is provided on the outermost surface of each display device or the surface of the front panel thereof as described above.

[Examples]

Further, the present invention will be described in detail by way of examples, but the invention is not limited by the examples.

Example 1

(Manufacture of acrylic substrate)

The particles composed of a copolymer of methyl methacrylate and methyl acrylate (glass transfer point: 130 ° C) are melt-kneaded and passed through a filter to remove impurities while the polymer is self-expanded by melt extrusion. The gap between the molds is extruded. Then, the polymer was cooled to 1.2 times in the longitudinal direction, and then extended to 1.5 times in the lateral direction to obtain an acrylic substrate having a thickness of 40 μm.

(Preparation of a composition for forming a resin layer)

100 parts by mass of tetraethylene glycol diacrylate (manufactured by Toagosei Co., Ltd., "M240"), and 4 parts by mass of an initiator (manufactured by BASF Corporation, "Irg184") were dissolved in methyl isobutyl ketone 150 mass. A composition for forming a resin layer was prepared.

In addition, the composition of the composition for resin layer formation is shown in Table 1.

(Preparation of Composition 1 for Hard Coating Formation)

50 parts by mass of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.), urethane urethane (manufactured by Nippon Synthetic Chemical Co., Ltd., "UV1700B", 10-functional, weight average molecular weight: 2,000 50 parts by mass and 4 parts by mass of an initiator (manufactured by BASF Corporation, "Irg 184") were dissolved in 150 parts by mass of methyl isobutyl ketone to prepare a composition 1 for forming a hard coat layer.

(Manufacture of optical laminate)

The resin layer-forming composition was applied onto the acrylic substrate by a die coating method, and dried at 70 ° C for 1 minute to evaporate the solvent, and the coating amount after drying was 4 g/m ² (dry film thickness: 3.5 μm). The method forms a resin layer. The coating film obtained was irradiated with ultraviolet rays at an irradiation amount of 70 mJ/cm ^{2 to} semi-harden the coating film (semi-cured state).

Then, the composition for forming a hard coat layer 1 was applied onto the resin layer formed in the above manner by a die coating method, and dried at 70 ° C for 1 minute to evaporate the solvent, and the coating amount after drying became 8 g/m. ^The hard coat layer 1 was formed in the form of ² (dry film thickness: 7 μm). The coating film obtained was irradiated with ultraviolet rays at an ultraviolet irradiation amount of 200 mJ/cm ^{2 to} completely cure the coating film (completely cured state), thereby obtaining an optical layered body.

Examples 2 to 16 and Comparative Examples 1 to 10

An optical layered body was obtained in the same manner as in Example 1 except that the composition of the resin layer-forming composition was changed to those shown in Tables 1 to 3.

Example 17

An optical layered body was obtained in the same manner as in Example 1 except that the hard-coat layer-forming composition 2 prepared in the following manner was used as the composition for forming a hard-coat layer instead of the hard-coat layer-forming composition 1 described above. .

(Preparation of Composition 2 for Hard Coating Formation)

30 parts by mass of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.), urethane acrylate (manufactured by Arakawa Chemical Industries Co., Ltd., "BS577", 6-functional, weight average molecular weight: 1,000) 20 parts by mass, 20 parts by mass of a monomer (manufactured by Toagosei Co., Ltd., "M315", trifunctional), and 4 parts by mass of an oligomer containing a quaternary ammonium salt (manufactured by TAISEI FINE CHEMICAL Co., Ltd., "1SX3000") 4 parts by mass of the initiator (manufactured by BASF Corporation, "Irg 184") was dissolved in 130 parts by mass of methyl isobutyl ketone and 20 parts by mass of N-butanol to prepare a composition 2 for forming a hard coat layer.

The optical layering system obtained in Example 17 contained an antistatic agent in the hard coat layer and thus had antistatic properties.

The optical laminates obtained in Examples 1 to 17 and Comparative Examples 1 to 10 were subjected to the following evaluations. The results are shown in Tables 1 to 3.

(The length of the ridge line in the reference length of 30 μm)

The cross section in the thickness direction of the obtained optical layered body was imaged by a scanning transmission electron microscope (STEM), and the measurement was performed based on the above-described "measurement method of the length of the ridge line in the reference length of 30 μm".

(the difference between the reference height and the reference depth)

As shown in Fig. 4, in the cross section in the thickness direction of the optical layered body, the acrylic substrate-resin layer interface has ridge lines having a mountain portion and a valley portion, and the y-axis is in the thickness direction of the optical layered body (where The resin layer side is a positive direction), an xy plane which is an x-axis in a direction perpendicular to the y-axis, and a reference length L of 30 μm in the x-axis direction, in the minimum point 4b of the ridge line in the reference length L Select 3 points (4b-1) from the smallest of the y coordinates, and use the average y coordinate As the reference depth 5b, on the other hand, among the maximum point 4a of the ridge line in the reference length L, three points (4a-1) are selected from the largest y coordinate, and the average y coordinate thereof is used as a reference. The height 5a is the difference (absolute value) between the reference depth 5b and the reference height 5a as the difference between the reference depth 5b and the reference height 5a.

(average tilt angle θa)

As shown in Fig. 5, in the cross section in the thickness direction of the optical layered body, the acrylic substrate-resin layer interface has a ridgeline having a mountain portion and a valley portion, and the y-axis is in the thickness direction of the optical layered body (wherein the resin The layer side is a positive direction), the xy plane is an x-axis in a direction perpendicular to the y-axis, and a reference length L of 30 μm is taken in the x-axis direction, and the extreme value point of the ridge line is determined at the reference length L (maximum value) Point 4a and minimum point 4b), the sum of the height difference (h ₁ ~ h ₁₂ , absolute value) of all the adjacent extreme points is recorded as the total height difference ΣH, at this time, tan ^-1 (total height) The value indicated by the difference H/reference length L) is taken as the average inclination angle θa.

(average interval Sm of the bumps)

The measurement was carried out in accordance with JIS B0601 (1994).

(adhesiveness)

Based on JIS K 5600, a hard coating of an optical laminate was drawn in a square of 1 mm square and a total of 100 squares, and a 24 mm Cellotape (registered trademark) manufactured by Nichiban Co., Ltd. was used for peeling test five times in a row to calculate the residue. The number of squares.

According to the number of squares that were not peeled off, the evaluation was performed as follows. ○ Above grade is preferred as a product.

A: 90-100

B: 80-89

C: 50-79

D: not up to 50

(interference fringes)

After attaching a black tape to the surface opposite to the hard coat layer of the optical layered body, the presence or absence of interference fringes was visually evaluated under a three-wavelength tube fluorescent lamp. The case where the invisible interference fringes are inscribed is denoted by A, the case where it is slightly visible is denoted by B, and the case where it is visible is denoted by C.

(manufacturing processability)

A tensile test was carried out at the stage where the resin layer-forming composition was applied onto an acrylic substrate and dried. The degree of stretching was set to 2.2 N/cm.

As a result, the case where the film was not broken at the time of stretching was evaluated as "good", and those who had problems in the manufacturing process even if a slight break occurred were evaluated as "poor".

Since the physical properties of the substrate of the optical layering system in which the workability is "defective" are weakened, even if the resin layer or the hard coat layer is cured, the pencil hardness (JIS K5600-5-4) is not 2H or more.

(haze)

The haze value (%) of the optical laminate was measured in accordance with JIS K-7136 using a fog meter (manufactured by Murakami Color Research Laboratory, product number: HM-150), and evaluated according to the following evaluation criteria.

A: Haze value is below 0.8

C: haze value exceeds 0.8

(surface resistance)

The surface resistivity of each of the optical laminates produced in the above Examples and Comparative Examples was measured using a surface resistance value measuring device (Hiresta HT-210, manufactured by Mitsubishi Petrochemical Co., Ltd.).

ND: not measured

ND: not measured

ND: not measured

PEG di(meth)acrylate 1: tetraethylene glycol diacrylate (manufactured by Toagosei Co., Ltd., "M240", molecular weight: 286)

PEG di(meth)acrylate 2: triethylene glycol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., "Light ester 3EG", molecular weight: 270)

PEG di(meth)acrylate 3: tetraethylene glycol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., "Light ester 4EG", molecular weight: 314)

Maleic acid imide polymer: (manufactured by Toagosei Co., Ltd., "UVT302")

PETA: Pentaerythritol triacrylate

Polyfunctional polymer: manufactured by Arakawa Chemical Industry, "BS371"

Polyfunctional oligomer: manufactured by First Industrial Pharmaceutical Co., Ltd., "R1403"

Monomer 1: dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

Monomer 2: o-phenol EO modified acrylate, M106 manufactured by East Asia Synthetic Co., Ltd.

Quaternary ammonium salt: manufactured by Colcoat, "Colcoat NR121X"

ATO particles: methyl isobutyl ketone dispersion doped with antimony tin oxide, manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd., "EPT5DL2MIBK"

Reactive cerium oxide: manufactured by Nissan Chemical Industry Co., Ltd., "MIBKSD", average particle size: 12 nm

Zirconium oxide: MEK dispersion of zirconia (solid content component 30% dispersion, manufactured by 堺Chemical Industries, "SZR-K 4nm")

MIBK: methyl isobutyl ketone

PGME: propylene glycol monomethyl ether

MEK: methyl ethyl ketone

[Industrial availability]

The optical laminate of the present invention can be preferably used for a cathode ray tube display device (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), a touch panel, an electronic paper, and an action. A display such as a telephone, especially a high-definition display.

1‧‧‧Acrylic substrate

2‧‧‧ resin layer

3‧‧‧hard coating

Claims (6)

An optical laminate having a resin layer on one surface of an acrylic substrate, a cross section in the thickness direction of the optical laminate, and an acryl line-resin layer interface having ridge lines having a mountain portion and a valley portion, and the above The length of the ridge line in the reference length 30 μm in the direction perpendicular to the thickness direction of the optical layered body is 31 to 45 μm. The optical laminate according to the first aspect of the invention, wherein the cross section of the optical laminate in the thickness direction of the optical laminate has a reference length of 30 μm perpendicular to the thickness direction of the optical laminate, and the valley of the acrylic substrate-resin layer interface From the bottom of the deepest valley, the average depth of the top three in the order of depth is used as the reference depth, and then the average height of the top three in the order of the top of the mountain from the highest peak of the acrylic substrate-resin layer interface As the reference height, the height difference between the reference height and the reference depth is 0.3 to 3.5 μm. An optical laminate having a resin layer on one surface of an acrylic substrate, a cross section in the thickness direction of the optical laminate, and an acryl line-resin layer interface having ridge lines having a mountain portion and a valley portion, and the above The length of the ridge line in the reference length 30 μm in the direction perpendicular to the thickness direction of the optical layered body is 31 to 45 μm, and the average inclination angle θ a of the ridge line is 15 to 48°. An optical laminate having a resin layer on one surface of an acrylic substrate, a cross section in the thickness direction of the optical laminate, and an acryl line-resin layer interface having ridge lines having a mountain portion and a valley portion, and the above The length of the ridge line in the reference length of 30 μm in the direction perpendicular to the thickness direction of the optical layered body is 31 to 45 μm, and the average interval Sm of the unevenness shown by the ridge line is 0.5 to 7 μm. A polarizing plate which is applied to the first or second patent range of at least one area layer of the polarizing film The optical laminate is formed. An image display device comprising the optical laminate of claim 1 and/or the polarizing plate of claim 5 of the patent application.